Note: Descriptions are shown in the official language in which they were submitted.
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Cable car and method for operating a cable car
The present invention relates to a method for operating a cable car with which
a number of
vehicles hanging on a hoisting cable are moved between at least two stations
and with which
the deflection of the vehicle from the vertical is measured with a sensor on
at least one
vehicle of the cable car. Furthermore, the invention relates to a
corresponding cable car.
A cable car with vehicles hanging on a revolving cable, whether permanently
coupled or
detachably coupled, is subject to special safety requirements. This is
especially true, but not
exclusively, for cable cars for carrying people. A safety risk is the swinging
motion of a
vehicle, because it can lead to a collision of the vehicle with stationary
facilities of the cable
car, such as a cable car tower, with overhead lines for energy and/or data
transmission
extending between the cable car towers, or with a component at a station
entrance, or with
other vehicles. In the worst case, it may occur that the vehicle gets pulled
off the cable and
crashes or that the cable derails. The swinging motion of the vehicle is
usually caused by the
application of external forces to the vehicle, such as wind or the deliberate
rocking of the
vehicle caused by passengers. But even one-sided loading of the vehicle,
especially in
combination with wind, can lead to the swinging motion of the vehicle.
The monitoring of the swinging motion of the vehicles is usually the
responsibility of the
operating staff of the cable car, which must assess whether critical swinging
movements of
the vehicles during operation of the cable car may occur or not. If necessary,
the operating
staff has to reduce the cable speed, or to stop the cable car completely. The
operating staff
are usually provided with the measured values of wind sensors arranged along
the route.
However, it is in the rarest cases that the entire cable car route is visible
for the operating
staff and also the climatic conditions (e.g. fog, snow, rain, etc.) or the
lighting conditions (e.g.
dusk, night, etc.) can affect the view. In addition, a wind sensor detects
only the wind
conditions in the immediate vicinity of the wind sensor, but cannot provide
any information
regarding the wind at another point of the cable car. Therefore, it is
necessary that wind
sensors are attached at all neuralgic positions (e.g. exposed cable car
towers) of the cable
car, which increases costs. Usually there are requirements for the operating
staff to reduce
the transport speed if the wind speed exceeds a certain level, or to
completely discontinue
.. the operation of the cable car. This, of course, is a very conservative
approach, which
sometimes leads to a reduction in the transport speed or even stops the cable
car, although
this is not absolutely necessary.
Consequently, measures to make the monitoring of the swinging motion of
vehicles safer and
more reliable have already become known.
EP 1 837 264 A2 describes the use of inclination sensors on the vehicles to
detect the
deflection of a vehicle from a vertical. The measured values of the
inclination sensors are
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transmitted via a transmitter on the vehicle either via relay stations on the
cable car towers or
directly to a receiving station of a station. In case of excessive deflections
either the speed is
reduced or the cable car stopped.
AT 411 982 B also describes the use of inclination sensors on the vehicles to
detect the
deflection of a vehicle. In addition, the detection of the wind speed and wind
direction is
provided on the vehicle. The recorded data are evaluated and stored in the
vehicle itself.
When a vehicle passes through a station, the collected data can also be
transmitted to a
receiver and can be used to control the cable car.
Also in WO 95/30216 Al, the deflection of a vehicle is detected by means of an
inclination
sensor on the vehicle. In addition, each vehicle includes a unique identifier.
The vehicle
transmits the inclination information and the identifier to a receiver on a
cable car tower,
which forwards the inclination information and the identifier to a cable car
control unit for
evaluation.
A particular danger point is the entrance to a station of the cable car, since
many stationary
facilities are located near the vehicles. In addition, so-called outer guide
rail trumpets are
usually arranged in the area of the entrance to the station, in which the
detachable grip of the
vehicle on the cable is to enter for guidance. With strong deflections of the
vehicle at the
station entrance, it may happen that the outer guide rail trumpet is missed,
which can lead to
massive damage to the cable car and/or the vehicle or even to the vehicle
being pulled off
the cable. Swinging motion detection at the entrance to a station is therefore
particularly
critical and it is up to the operator of the cable car to ensure that there
will be no critical
situations during operation of the cable car, for example by the operating
staff monitoring the
information provided by the wind sensors arranged along the cable car.
EP 2 147 843 Al proposes to detect the swinging movement of a vehicle before
the station
entrance by means of a sensor in the station, in particular a laser scanner or
a camera, with
which the distance of the vehicle to the station is detected at the same time,
in order to
control the cable car drive depending on the swinging movement. Thus, a
swinging
movement of the vehicle transversely to the direction of travel before the
station can be
reliably detected. A detection of a potential hazard at the entrance of the
vehicle in the
station is not possible. For example, if the vehicle is approaching the
station in an inclined
position without swinging movement, the control device would not react.
It is therefore an object of the present invention to provide a method by
which the potential
hazard at the entrance of a vehicle in the station of a cable car can be
assessed more
reliably and reacted to accordingly.
This object is achieved in that the deflection of the vehicle is measured with
the sensor
before the station entrance and transmitted to the cable car control unit, in
that at the same
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time the occurrence of a wind gust before the station entrance is detected by
the cable car
control unit and that the cable car control unit controls a cable car drive as
a function of the
transmitted deflection and the detected wind gust. In this way, the cable car
control unit can
not only detect and evaluate a current deflection of a vehicle, but can now
also consider the
occurrence of wind gusts when the cable car drive is controlled. It was
recognized that above
all the combination of the deflection and the wind gust before or in the area
near the station
entrance gives rise to a considerable potential hazard, which can now be
recognized in time.
The cable car control unit can now react in time to such a potential hazard
and reduce, for
example, the driving speed of the cable car.
According to some embodiments disclosed herein, there is provided method for
operating a
cable car with which a number of vehicles hanging on a hoisting cable are
moved between at
least two stations and on at least one vehicle of the cable car, the
deflection of the vehicle
from the vertical is measured with a sensor, wherein the deflection of the
vehicle is measured
with the sensor before the station entrance and transmitted to the cable car
control unit,
wherein at the same time the occurrence of a wind gust as temporal change of
the wind
speed is detected by the cable car control unit with a wind sensor aranged on
a cable car
tower before the station entrance wherein the cable car control unit combines
the transmitted
deflection of the vehicle and the detected wind gust for controlling a cable
car drive as a
function of the transmitted deflection and of the detected wind gust.
According to some embodiments disclosed herein, there is provided cable car
with a number
of vehicles hanging on a hoisting cable, which are movable between at least
two stations,
wherein a sensor for detecting the deflection of the vehicle from the vertical
is arranged on at
least one vehicle of the cable car, wherein a cable car control unit is
provided, which is
connected to a cable car drive and controls the cable car drive and a
transmitting device is
arranged on the vehicle in order to transmit the deflection of the vehicle
measured by the
sensor before the station entrance to a receiver in the area of the station,
whereas the
receiver being connected to the cable car control unit and the receiver
transmitting the
deflection to the cable car control unit, wherein before on a cable car tower
before the station
entrance a wind sensor is arranged which is connected to the cable car control
unit and
which detects the occurrence of a wind gust, as temporal change of the wind
speed, before
the station entrance and transmits the detected occurrence of a wind gust to
the cable car
control wherein the cable car control unit combines the transmitted deflection
of the vehicle
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and the detected wind gust for controlling the cable car drive as a function
of the transmitted
deflection and the detected wind gust.
By additional detection of the direction of the wind gust the cable car
control unit is enabled to
respond even better to a potential hazard, because not every wind gust from
any direction is
equally dangerous. Therefore, in an advantageous embodiment, only wind gusts
from a
defined direction can be taken into account or wind gusts from different
directions can be
considered differently.
In order to still allow an emergency stop of the vehicle before the station
entrance, it is
preferably provided that the deflection of the vehicle and the occurrence of
the wind gust, and
possibly also the direction of the wind gust, are detected by the cable car
control unit at a
distance before the station entrance, which is larger than the braking
distance of the vehicle.
In a particularly advantageous embodiment, a radio transponder is provided on
the vehicle as
transmitting device and the receiver is designed as a reader for the radio
transponder. Radio
transponders are small, compact components that can be easily arranged on the
vehicle. If
the radio transponder is embodied in a particularly advantageous embodiment as
a passive
radio transponder, an independent power supply of the vehicle can be omitted,
because the
vehicle can then be supplied with electrical energy via the radio transponder.
For this
purpose, the reader can emit a polling signal via a transmitting antenna,
which the radio
transponder receives and uses to obtain the electrical energy for operating
the radio
transponder and the sensor.
The present invention is described in greater detail below with reference to
the Figures 1 to 4,
which show advantageous embodiments of the invention in an exemplary,
schematic and
non-limiting manner. In the figures
Fig. 1 shows a station area of a cable car with monitoring of the deflection
of a vehicle,
Fig. 2 shows a schematic representation of the procedure according to the
invention for
monitoring the deflection of a vehicle,
Fig. 3 shows the use of directional ranges in the evaluation of the wind gusts
and
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Fig. 4 the use of a radio transponder for transmitting the deflection to the
cable car control
unit.
Fig. 1 shows a station 2 of a cable car 1 and a part of the transport route of
the cable car 1
with a cable car tower 3 before the station entrance. Vehicles 4 of the cable
car 1 are
transported by means of a hoisting cable 5, which is turned round in the
stations 2 via cable
pulleys. One cable pulley 6 is driven by a cable car drive 7, wherein the
cable car drive 7 is
controlled by a cable car control unit 8. At the station entrance 9, an outer
guide rail trumpet
may be arranged, in which the detachable grip 11 of the vehicle 4 is to enter
in order to
guide the vehicle 4 into the station 2. For the invention, it is irrelevant
whether the vehicles 4
10 are permanently coupled to the hoisting cable 5, or whether the vehicles
4 can be coupled to
the hoisting cable 5 (for example by means of well-known detachable grips).
Likewise, it is
irrelevant for the invention whether persons and/or material are transported
by the cable
car 1. A number of support cables between the stations on which the vehicles 4
are moved
may also be provided.
On a vehicle 4, a sensor 12 for detecting the deflection of the vehicle 4 from
a vertical is
arranged. Above all, the deflection a in the direction y transverse to the
transport direction x
(Fig. 2) is of interest. But also the largest deflection a, which does not
necessarily occur in
the transverse direction y, could be detected. Any suitable sensor is may be
used for this
purpose, for example a position sensor or an acceleration sensor. In the case
of an
acceleration sensor, the values supplied by the sensor 12 at a specific
sampling rate are
written to a memory on the vehicle 4, for example. With these values, it is
then always
possible to deduce a current deflection a.
With the sensor 12, the deflection a is generally detected and transmitted to
the cable car
control unit 8. This is preferably done with a wireless communication
connection, such as
radio. For this purpose, a transmitting device 13 can be provided on the
vehicle 4, which
transmits the detected deflection a of the vehicle 4 to a receiver 14 in the
station 2 or in the
area near the station 2. The receiver 14 is connected to the cable car control
unit 8 and
forwards the received signal or the information transmitted therein to the
cable car control
unit 8.
In addition, the occurrence of wind gusts B is detected before the station
entrance 9. For this
purpose, for example, a wind sensor 15 may be provided before the station
entrance 9, for
example at the last cable car tower 3 before the station 2. The wind sensor 15
transmits the
detected values to the cable car control unit 8 via a suitable communication
connection. For
this purpose, a wired or wireless communication connection can be provided.
For example,
in the case of a wireless communication connection, the wind sensor 15 could
send its
values via radio to the receiver 14 in the station 2. The wind sensor 15
measures either the
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wind speed vw or directly wind gusts B. Wind gust B is understood to be the
temporal change
of the wind speed vw. If the wind speed vw is detected, a value for the wind
gust B can be
dv
B=
obtained by time derivative dt . This can also be done in the cable car
control unit 8. In
principle, a wind sensor 15 for detecting the wind speed vw or a value for a
wind gust could
also be provided on the vehicle 4, whereas substraction of the airstream of
the vehicle 4
would be advantageous. In this case, the wind speed vw or the value for the
wind gust could
also be sent with transmitting device 13 to the receiver 14 of the station 2
and thus to the
cable car control unit 8.
It can also be provided to detect the wind direction with the wind sensor 15.
Thus, not only
the occurrence of wind gusts B can be detected, but also from which direction
R the wind
gust B occurs. The direction R of a wind gust B can considerably influence the
swinging
motion of the vehicle 4. For example, a wind gust B, which acts on the vehicle
4 in the
transport direction x along the route, from the front or from behind, may be
significantly worse
than a wind gust B in the transverse direction y. If a wind gust B hits the
vehicle 4 laterally,
the deflection in the transverse direction y is directly given, but the
contact surface of, for
example, a chair as vehicle 4 is very small. However, if a wind gust B hits a
chair with an
open bubble frontally, the contact surface is much larger, which can also lead
to a massive
deflection in the transport direction x and transverse direction y.
The cable car control unit 8 can now combine the current deflection a and the
occurrence of
wind gusts B and can control the cable car drive 7 accordingly. To this end,
the direction R of
the wind gust B can also be taken into account. It has been found in the
operation of a cable
car 1 in practice that in particular the combination of deflection a, for
example, due to a one-
sided loading of the vehicle 4, and the occurrence of wind gusts B in the area
of the station
entrance 9, possibly as a function of the direction R of the wind gust B, is
especially
dangerous. In this case, the vehicle 4 does not even have to approach the
station entrance 9
while swinging. However, if the vehicle 4 swings on the hoisting cable 5, then
the greatest
deflection of the swinging movement could be used as a deflection a. At a
certain deflection
a and when certain wind gusts B occur, large swinging motions of the vehicle 4
in the
transverse direction y may occur, which may result in the vehicle 4 touching a
stationary
component of the station 2 at the station entrance 9 or even missing the outer
guide rail
trumpet 10. Both can lead to severe accidents and damage to the cable car 1
and/or the
vehicle 4. By the inventive combination of the deflection a with the detection
of the
occurrence of wind gusts B the latter can be effectively prevented.
It makes sense to specify an allowable deflection amax and an allowable
maximum wind gust
Bma. (FIG. 2). If both permissible values are exceeded before the station
entrance 9, then for
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example the cable car drive 7 can be controlled by the cable car control unit
8 in order to
reduce the driving speed or to stop the cable car 1. Of course, several
thresholds could be
defined for the deflection a and/or for the wind gust B. Thus, the current
state of the vehicle 4
and the wind at the station entrance 9 can be classified from being less
critical to critical. In
the case of being less critical, for example, the driving speed is reduced
(also possible in
several stages) and, in the case of critical conditions, the cable car 1 is
stopped. The cable
car control unit 8 could of course weight the deflection a and the wind gust B
differently, for
example in order to take account of special conditions or the design of a
cable car 1. The
latter, or fixed thresholds, could also be changed in the operation of the
cable car 1, in order
to consider information acquired during the operation of the cable car.
In addition, the direction R of the wind gust B can also be detected and taken
into account in
the cable car control unit 8 during the control of the cable car drive 7. For
example, for
different directions R, or ranges of directions R, different thresholds for
the deflection a
and/or the wind gust B could be deposited. But it could also be provided to
take into account
only wind gusts B from a certain direction R, or from a range of directions R.
For example,
only wind gusts B in the direction of travel x or only wind gusts B in a range
of directions RB
around the direction of travel x could be taken into account, as shown in Fig.
3. In the cable
car control unit 8 the wind gust B could also be weighted differently
depending on the
direction R, so that critical directions R of wind gusts B are more critical
than others. Which
wind gusts B with which direction R are taken into account in which manner in
the cable car
control unit 8 can, of course, be defined and can depend on the cable car
type, on the
surroundings of the cable car 1, on the operating parameters of the cable car,
etc. Of course,
this can also be changed during operation of the cable car 1.
The detection of the wind speed vw or the wind gust B, and optionally the
direction R, and the
deflection a preferably takes place in such a distance before the station
entrance 9, that the
vehicle 4 may still be safely braked before the station 2. On the other hand,
the detection
should not take place at too large a distance before the station entrance 9,
because in this
case the detected values would no longer have any relevance for the situation
of the station
entrance 9. Which distance is appropriate, of course, depends on the
respective cable car 1.
In most cases, the detection will have to be aimed for in a range smaller than
80 m before
the station entrance 9. The values of the deflection a and the detection of
the wind gust B,
and optionally the direction R, are therefore preferably detected at least by
the braking
distance BW of the vehicle 4 before the station 2 (Fig. 1). The braking
distance BW of the
vehicle 4 is usually known. In conventional cable cars 1 with maximum travel
speeds of
typically 7 m/s, the braking distance BW is approximately 25-40 m in the event
of an
emergency stop. Often there is a cable car tower 3 in this area before the
station 2. Thus, the
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detection of the wind speed vw or the wind gust B, and optionally the
direction R, could occur
at a cable car tower 3 before the station 2.
The receiver 14 is therefore preferably arranged such that the transmission
range of the
transmitting unit 13 is sufficient to be able to receive the deflection a from
a sufficiently large
distance. Preferably, the receiver 14 is arranged inside the station 2, but
could also be
arranged in the area of the station 2 before the station entrance 9. For
example, the receiver
14 could also be arranged on a cable car tower 3 before the station 2 and be
connected to
the cable car control unit 8 via a corresponding communication line.
Especially advantageous for the transmission of information from the vehicle 4
to the station
2 is the use of radio transponders RF as a transmitting device 13 on the
vehicle 4, such as
RFID (Radio Frequency Identification) transponder (often called RFID tag), as
is explained
by means of Fig. 4. A memory unit 33 is provided in the radio transponder RF
on the vehicle
4, in which, for example, values for the deflection a and optionally also
values for the wind
speed v, or for wind gusts B, and optionally the direction R, can be stored.
The sensor 12 for
detecting the deflection a could store its values, for example, in the memory
unit 33 of the
radio transponder, and a wind sensor 15 could do this as well, if the latter
is provided on the
vehicle 4. Such a radio transponder RF can have a very small size and can
therefore be
used very flexibly. In the effective range of a transmitting antenna 31, which
transmits a
polling signal 34, the radio transponder RF responds with a response signal
35, which
comprises the deflection a, and optionally also a value of the wind gusts B
and possibly the
direction R. The response signal 35 is received by the transmitting antenna 31
and forwarded
to a reader 30 which decodes the required values from the response signal 35.
The reader
is connected to the cable car control unit 8 and can send the obtained values
to the cable
car control unit 8. A plurality of transmitting antennas 31 can be connected
to a reader 30, as
25 indicated in Fig. 4. The receiver 14 in the station 2 could therefore be
designed as a reader
30 with a transmitting antenna 31. The transmitting antenna 31 would have to
be designed in
such a way that the polling signal 34 is transmitted as far from the station 2
to the route that
information from the vehicle 4 can be obtained as early as possible.
The supply of a vehicle 4 with electrical energy is cumbersome in practice,
because usually
30 an energy storage device must be provided on the vehicle 4 and the
energy storage must be
charged, for example, during the travel through the station. Therefore, it is
often desirable in
a cable car 1 not to use an electric power supply on the vehicles 4. This
contradicts of course
the requirement to detect the deflection a of the vehicle 4 and to transmit
the latter to the
cable car control unit 8.
In a particularly advantageous embodiment, therefore, a passive radio
transponder is used
on the vehicle 4, for example a passive RFID transponder, because no power
supply of the
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radio transponder RF on the vehicle 4 is necessary in this case. A passive
radio transponder
is active only in the effective range of a transmitting antenna 31 of a reader
30 spanning an
electromagnetic field, since the passive radio transponder RF acquires the
electrical energy
to operate from the electromagnetic signal emitted by the transmitting antenna
31, which is
received with a receiving antenna 32 in the radio transponder RF. Thus, the
sensor 12, and
possibly also a wind sensor 15, on the vehicle 4 could receive the required
electrical energy
from the passive radio transponder RF.
When the vehicle 4 approaches the station 2, the passive radio transponder RF
at the
vehicle 4 reaches the effective range of the transmitting antenna 31, whereby
the power
supply is enabled. Then, the sensor 12, and possibly also a wind sensor 15,
are read and the
detected value of the deflection a, and possibly the occurrence of a wind gust
B and a
direction R, are sent with the response signal 35 to the reader 30. There are
also radio
transponders RF with a sensor input, so that a sensor 12, and possibly also a
wind sensor
15, can also be connected directly to the radio transponder RF in order to be
read out directly
via the radio transponder RF.
Of course, other information could also be stored in the memory unit 33 of the
radio
transponder RF. For example, a unique vehicle identifier FID could be stored
in each vehicle
4 in the storage unit 33, which could also be transmitted to the cable car
control unit 8.
If the effective range of the transmitting antenna 31 does not reach far
enough to poll the
information required by the vehicle with a radio transponder RF before the
braking distance
BW, it could also be provided to arrange the reader 30 with a transmitting
antenna 31 outside
the station 2, for example, at the last cable car tower 3 before the station
2. The reader 30
may be connected to the cable car control unit 8 or the receiver 14 in the
station 2 (wireless
or wired) to transmit the values of the deflection a, and possibly also the
wind gust B and a
direction R.
In addition, values of the deflection a along the route between the stations 2
could also be
collected with a radio transponder RF. If a power supply on the vehicle 4 were
present, for
example, the sensor 12 could be read out at a predetermined sampling rate and
stored in the
memory unit 33. In the area of the station 2, the memory unit 33 can then be
read out and
the stored values can be analyzed by the cable car control unit 8. From this,
the cable car
control unit 8 can obtain important information about the conditions present
along the route,
which can also be used to control the cable car drive 7. When using a passive
radio
transponder RF, a reader 30 could be arranged at least on certain cable car
towers along the
route, whereby the sensor 12, and preferably also the vehicle identifier FID,
can be read in
the area of the cable car tower. The thus detected sensor value can be stored
in the memory
unit 33 and/or can be transmitted from the cable car tower to the cable car
control unit 8. In
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the station 2, the storage unit 33 could then be read out with a reader 30. In
this case, an
electric power supply is required on the cable car tower and possibly also a
data connection
to the cable car control unit 8.
The communication path between the vehicle 4 and the cable car control 8, i.e.
for example,
the cable car control unit 8, the reader 30, the transmitting antenna 31, the
radio transponder
RF, can of course also be designed to be functionally failsafe, for example,
according to a
required safety integrity level (SIL) in order to ensure safe communication in
the sense of
functional safety (i.e., in the sense that an error is detected immediately
and the system then
preferably switches to a safe state). For this purpose, well-known mechanisms,
such as a
multi-channel hardware, redundancy in the data, error detection and error
correction
methods in the data transmission, etc., can be provided. For example, a
timestamp could be
added to each signal 34, 35 or to the data carried therein. If the time bases
of the reader 30
and the cable car control unit 8 are synchronized, a deviation of the time
stamp to the
synchronized control time can be detected and could, e.g., result in a
shutdown of the cable
.. car 1. It may further be provided that the memory unit 33 of the radio
transponder RF must
be read several times within a predetermined period of time in order to verify
the transmitted
data. The data transmitted in the response signal 35 could be protected by
redundant data,
for example, by a CRC (cyclic redundancy code). Of course, further measures to
ensure the
functional safety are also conceivable.
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